Until now, rumors indicated that Apple will unveil the next generation MacBook Pros with Retina Display, iOS 6 - its next generation mobile operating system, release update for iCloud and OS X Mountain Lion at next week's WorldWide Developer Conference.

But looks like Apple may have more surprises for us. 9to5Mac now reports that Apple will update at least four out of their five Mac products. According to them, "WWDC 2012 might be the biggest simultaneous launch of new Macs in Apple’s history".

9to5Mac reports:We are hearing that Apple will release two configurations of the redesigned 15-inch MacBook Pro, but it is unclear what will happen to the other MacBook Pro screen sizes. We previously reported that Apple is working on a version of the 11 inch and 13 inch MacBook Airs with Retina Displays, and we are led to believe that these new ultra-thin notebooks will serve as the second Mac update announcement at WWDC. Apple will likely release two new configurations of both MacBook Air screen sizes.

The third new update will likely be a refresh to the iMac line. Apple last updated the iMacs in May 2011 with faster processors, a vastly-improved graphics system, Thunderbolt, and a FaceTime HD camera. [...]

[..] Apple is also planning to refresh a fourth piece of their Mac line, and this leaves the Mac mini and the Mac Pro. We are currently unsure whether or not the Mac Pro or Mac mini will be the fourth Mac updated at the conference, but both Macs are due for a refresh, especially the Mac Pro.

9to5Mac also claims that according to their sources, Apple will also introduce new and updated accessories at the event, though the exact details are not yet known.